Environmental Impact

The environmental impacts of installing HVDC cable under or on the ocean floor are minimal and temporary in duration.

Cable installation will be scheduled when it will have the least impact on those who make their living harvesting resources from the ocean or migratory species such as whales. Other plants and animals found in the ocean like fish stocks are not impacted by this kind of project. 

Enl Cape Ray

We know there is minimal impact based on several other successful submarine HVDC electric transmission cable projects that have been completed around the world. The following provides a summary of the typical impacts of undersea, buried HVDC cables:

BassLink - Australia - Tasmania

Ecological effects have been transient and minor for cable buried in soft sediments.

Unburied cable on hard substrate is colonizable and quickly utilized by reef species within the 3.5 year inspection timeframe.

Magnetic and electric fields do not appear to affect utilization by reef species.

SwePol - Sweden – Poland

Studies prior to construction and one year after construction activity show no visible change to the seabed where the cable is buried in soft sediments.

No identifiable changes in benthic species composition, abundance, or biomass related to cable construction.

In the areas of least dynamic seabed, minor indications of construction remained one year after installation.

Monopole design creates detectable electromagnetic changes up to 20m from the cable, significantly greater than those from a dipole cable like Atlantic Link.

Baltic Cable - Sweden - Germany

No observed negative environmental impacts over several years on operating cables in the Baltic Sea.

Findings during the probationary period of the cable operation conclude:

  • No impact on benthic flora or fauna along the cable route or at electrode sites.
  • No major impact on fish; It does appear to locally confuse eels, but is not an obstacle to eel migration out of the Baltic Sea.

TransBay Cable - San Francisco, CA

Survey and modeling of the magnetic field of the Trans Bay Cable do indicate a detectable field, but unrelated anomalies generated by unrelated infrastructure, such as large bridges, can be up to 100 times larger.


Does this kind of cable affect marine life?

After the cable is buried on the ocean floor, will it affect marine life?

How long will it take, after burial on the ocean floor is completed, for things to return to normal?

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